JP2001219560A - Ink jet recording head - Google Patents

Abstract

(57) [Problem] To provide an ink jet recording head capable of reducing the size of the recording head, enabling the use of multicolor ink, and narrowing the nozzle pitch without deteriorating the image quality. SOLUTION: The pressure generating chambers 2 are arranged in a row, the nozzle openings 3 communicating with the respective pressure generating chambers 2 are arranged in a row, and a piezoelectric vibrator 6 for generating a pressure in each of the pressure generating chambers 2 is provided.
For one row of pressure generating chambers 2, there are first and second ink storage chambers 4 </ b> A and 4 </ b> B extending in the direction in which the pressure generating chambers 2 are arranged. A row of the first ink supply ports 15A that communicate with each other, and the second ink supply ports 15 that communicate the second ink storage chamber 4B with the pressure generation chamber 2.
The row B is arranged in parallel with one end of each pressure generating chamber 2 so that different colors of ink are ejected in the same row of nozzle openings 3, so that the size of the print head itself is reduced. Even if the number of ink storage chambers is increased by increasing the number of ink colors to be used, the size of the recording head itself does not increase so much.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head for recording an image or a character on a recording sheet by discharging ink droplets from nozzle openings by vibration of a piezoelectric vibrator or the like.

[0002]

2. Description of the Related Art In general, an ink jet recording head (hereinafter, referred to as a "recording head") to which a piezoelectric vibrator in a flexural vibration mode is attached, as shown in FIGS.
An actuator unit 1 in which a plurality of pressure generating chambers 2 and a piezoelectric vibrator 6 corresponding to each pressure generating chamber 2 are formed, and a nozzle opening 3 and an ink storage chamber 4 are formed and adhered to the lower surface of the actuator unit 1 Channel unit 5
The piezoelectric vibrator 6 generates pressure in the pressure generating chamber 2 by flexural vibration of the piezoelectric vibrator 6, and ejects ink droplets from the nozzle openings 3.

The actuator unit 1 includes a pressure generating chamber forming substrate 10 in which a space for forming the pressure generating chamber 2 is formed, and a vibration which is located on the upper surface of the pressure generating chamber forming substrate 10 and closes an upper surface opening of the space. And a plate 11.
The pressure generating chamber 2 is formed in a long hole shape. One end of the pressure generating chamber 2 communicates with the ink storage chamber 4, and the other end communicates with the nozzle opening 3.

The flow channel unit 5 includes a storage chamber forming substrate 16 in which a space for forming the ink storage chamber 4 is formed, and a nozzle plate formed with a nozzle opening 3 and located on the lower surface of the storage chamber forming substrate 16. 17 and the storage chamber forming substrate 1
6 and a supply port forming plate 18 located on the upper surface of the nozzle 6. The storage chamber forming substrate 16 is formed with a nozzle communication port 9 communicating with the nozzle opening 3. Further, the supply port forming plate 18 is provided with the pressure generation chamber 2 from the ink storage chamber 4.
An ink supply port 15 for supplying ink to the pressure generating chamber 2 is formed, and a communication port 8 for communicating the pressure generating chamber 2 with the nozzle communication port 9 and the nozzle opening 3 is formed. In the figure, reference numeral 24 denotes an ink inlet for introducing ink from an ink cartridge (not shown) into the ink storage chamber 4.

In this example, a recording head that performs printing using six color inks is shown. In this recording head, three sets of actuator units 1 provided with two rows of pressure generating chambers 2 arranged in the recording paper feed direction are provided, and the actuator unit 1 is arranged in the width direction of the recording paper (the width of the recording head). (Scanning direction). The flow path unit 5 is provided with six ink storage chambers 4 corresponding to the rows of the pressure generating chambers 2 arranged in the width direction of the recording paper. Then, different colors of ink are ejected from the six rows of nozzle openings 3 corresponding to the rows of the pressure generating chambers 2.

The diaphragm 1 of the actuator unit 1
The lower electrode 19 is formed on the upper surface of the substrate 1. The lower electrode 19 is formed at a portion covering the upper part of the pressure generating chamber 2. The plate-shaped piezoelectric vibrators 6 are respectively formed on the upper surfaces of the lower electrodes 19, and the upper electrodes 20 are formed on the upper surfaces of the piezoelectric vibrators 6.

[0007] Terminals 21 that are electrically connected to the upper electrode 20 of each piezoelectric vibrator 6 are formed at both ends of the upper surface of the actuator unit 1. A flexible circuit board 22 is stretched on the upper surface of the terminal 21,
A drive signal is applied to the piezoelectric vibrator 6 via the first and upper electrodes 20.

In the recording head, when a drive signal is applied to the piezoelectric vibrator 6, the piezoelectric vibrator 6 contracts in the horizontal direction as shown in FIG. At this time, the lower surface side of the piezoelectric vibrator 6 fixed to the vibration plate 11 does not contract but only the upper surface side contracts, so that the piezoelectric vibrator 6 and the vibration plate 11 bend downward and compress the pressure generating chamber 2. . When the pressure in the pressure generating chamber 2 rises, ink in the pressure generating chamber 2 is ejected from the nozzle openings 3 as ink droplets 23, and dots are formed on recording paper or the like to perform printing. Next, when the piezoelectric vibrator 6 is discharged and returns to the original state, the pressure in the pressure generating chamber 2 is reduced, and new ink is supplied from the ink storage chamber 4 to the pressure generating chamber 2 through the ink supply port 15.

[0009]

However, in the above-described recording head, one ink storage chamber 4 corresponds to one row of the pressure generation chambers 2, and six ink storage chambers 16 are formed on one storage chamber forming substrate 16. A chamber 4 is formed, and six rows of nozzle openings 3 are formed.
Are ejected from the rows. Since the six ink storage chambers 4 are arranged in the lateral direction of the recording head, there is a problem that the lateral size of the recording head inevitably increases. Recently, it has been considered to increase the number of ink colors from the current six colors in order to further improve the print quality. However, if the number of colors is increased beyond the current level, the recording head becomes larger. In fact, it has not been realized because it is not preferable in terms of accuracy and accuracy.

In the above-described recording head, the nozzle pitch in the row of the nozzle openings 3 tends to be narrowed in recent years. By narrowing the nozzle pitch, there are many advantages that the size of the recording head can be reduced, accuracy in assembling the recording head also decreases, and image quality decreases when paper feeding becomes unstable. Because.

However, narrowing the nozzle pitch makes it difficult to fill a blank between the nozzle pitches with dots of a constant pitch, or a boundary between dot lines is generated, which tends to lower the image quality. The problem arises.

That is, as shown in FIG. 11A, the nozzle pitch n is eight times the dot line pitch p (for example, n = 8/720 inch, p = 1/720 inch).
h), the paper feed amount is set to m × n ± p (m
Is an integer greater than or equal to 0, m × n−p is a positive number, the same applies hereinafter), and a dot line in the second pass is followed by a dot line in the second pass (1 in the drawing; dots are indicated by oblique lines). It is printed, then the 3rd pass, 4th pass ...
The dot line of the eighth pass is printed immediately before the dot line of the first first pass, and the space between the nozzle pitches is sequentially filled. However, when dot lines are sequentially printed in this way, an error in the paper feed amount is accumulated between the dot lines in the eighth pass and the first pass, and the space cannot be sufficiently filled, or the first pass does not. The problem that the 8th pass is printed after the ink has dried and the boundary is visible tends to occur.

Therefore, as shown in FIG. 11 (b), by setting the paper feed amount to m × n ± 3p (or m × n ± 5p), blank spaces between nozzle pitches are scattered at regular intervals. Has been done.

Here, by narrowing the nozzle pitch n, the nozzle pitch is made six times as large as the dot line pitch n (for example, 6/720 inc.
h), as shown in FIG. 12A, if the paper feed amount is m × n ± 2p (or m × n ± 4p),
The dot line in the fourth pass overlaps the dot line in the first pass, and it is not possible to fill the space between the nozzle pitches (even if the paper feed amount is m × n ± 3p, the dot line in the third pass is A similar result is obtained by overlapping with the dot line of the eye). Therefore, when the nozzle pitch n is designed to be narrow, as shown in FIG. 12B, dot lines must be sequentially printed, and as described above, it is not possible to sufficiently fill the space or to make the boundary visible. Problem easily occurs.

The present invention has been made in view of the above circumstances, and it is possible to reduce the size of a recording head, use various types of inks, and reduce the nozzle pitch without deteriorating the image quality. It is an object of the present invention to provide an ink jet recording head which can be used.

[0016]

In order to achieve the above object, an ink jet recording head according to the present invention has a plurality of pressure generating chambers arranged in a line, and stores ink supplied to each of the pressure generating chambers. An ink jet recording head provided with a chamber and provided with a row of nozzles communicating with each of the pressure generating chambers, and a pressure generating element for generating pressure in each of the pressure generating chambers and discharging ink droplets from each nozzle. Wherein a first and a second ink storage chambers extending in the direction in which the pressure generation chambers are arranged are provided for one row of the pressure generation chambers, and the first ink storage chamber and the pressure generation chambers communicate with each other. Since the ink supply port row and the second ink supply port row communicating the second ink storage chamber and the pressure generation chamber are arranged side by side on one end side of each pressure generation chamber, different types in the same nozzle row are provided. No And summarized in that is adapted to be ejected click.

That is, the ink jet recording head of the present invention has first and second ink storage chambers extending in the direction in which the pressure generation chambers are arranged for one pressure generation chamber row. A first ink supply port array for communicating the chamber with the pressure generation chamber and a second ink supply port array for communicating the second ink storage chamber with the pressure generation chamber are arranged in parallel at one end of each pressure generation chamber. Thus, different types of ink can be ejected within the same nozzle row. As described above, since two different types of ink can be ejected from one row of pressure generating chambers, the size of the recording head itself is significantly larger than that of the conventional one that ejects one color of ink from one row of pressure generating chambers. Can be downsized. Further, even if the number of ink storage chambers is increased by increasing the number of colors of ink to be used, the size of the recording head itself does not need to be so large.

In the ink jet recording head of the present invention, when adjacent nozzles eject different types of ink in the same nozzle row, the nozzles ejecting the same type of ink are separated from each other. Therefore, even if the nozzle pitch is narrowed, the apparent nozzle pitch between the same types can be made sufficiently large. Therefore, the nozzle pitch can be made sufficiently small, the recording head can be miniaturized, and the accuracy decrease at the time of assembling the recording head decreases, and the image quality decreases when the paper feeding becomes unstable. In addition, there is no problem that the space cannot be sufficiently filled or the boundary is visible.

In the ink jet recording head of the present invention, when different types of ink ejected in the same nozzle row are inks of different colors, the size of the recording head is not increased and the multicolor ink is used. Rich expression is possible.

In the ink jet recording head according to the present invention, when the first and second ink storage chambers have a flat shape formed of a smooth curve, air bubbles hardly adhere to the flow path, and This makes it less likely that ejection failure or the like will occur.

In the ink jet recording head of the present invention, an ink introduction port for introducing ink into the first and second ink storage chambers is formed, and the ink introduction ports are arranged in one row in a direction orthogonal to the row of pressure generating chambers. In the case of the arrangement, ink can be easily introduced from an ink cartridge or the like, and the structure is not complicated.

In the ink jet type recording head of the present invention, when the ink having passed the first and second ink supply ports has first and second pressure generation chamber communication ports for guiding the ink to the pressure generation chamber, Since the ink that has passed through the first and second ink supply ports once flows into the pressure generation chamber via the first and second pressure generation chamber communication ports, the flow of the ink becomes smooth.

[0023]

Next, embodiments of the present invention will be described in detail.

FIGS. 1 and 2 are views showing an ink jet recording head of the present invention. This recording head is basically the same as that shown in FIGS. 7 to 9, and the same parts will be described with the same reference numerals.

The recording head includes an actuator unit 1 in which a plurality of pressure generating chambers 2 are arranged in a row and a piezoelectric vibrator 6 corresponding to each of the pressure generating chambers 2 is provided.
Ink storage chambers 4A and 4B that are attached to the lower surface of the actuator unit 1 and store the ink supplied to the pressure generation chamber 2 are formed.
And a flow path unit 5 in which nozzle openings 3 communicating with the flow passage unit 5 are arranged. Then, a pressure is generated in the pressure generating chamber 2 by the flexural vibration of the piezoelectric vibrator 6, and an ink droplet is ejected from the nozzle opening 3.

The actuator unit 1 has a pressure generating chamber forming substrate 10 in which a space for forming the pressure generating chamber 2 is formed, and a vibration which is located on the upper surface of the pressure generating chamber forming substrate 10 and closes an upper opening of the space. And a plate 11.
The pressure generating chamber 2 is formed in a long hole shape, and one end thereof communicates with the ink storage chambers 4A and 4B, and the other end communicates with the nozzle opening 3. Further, the pressure generating chambers 2 are provided so as to form two rows aligned in the recording paper feed direction.

The diaphragm 1 of the actuator unit 1
The lower electrode 19 is formed on the upper surface of the substrate 1. The lower electrode 19 is formed at a portion covering the upper part of the pressure generating chamber 2. The plate-shaped piezoelectric vibrator 6 is formed on the upper surface of the lower electrode 19, and the upper electrode 20 is formed on the upper surface of the piezoelectric vibrator 6.

The flow channel unit 5 includes the ink storage chamber 4.
Storage chamber forming substrate 1 in which spaces for forming A and 4B are formed
6, a nozzle plate 17 located on the lower surface of the storage chamber forming substrate 16 and a supply port forming plate 18 located on the upper surface of the storage chamber forming substrate 16 are laminated.

In the nozzle plate 17, the nozzle openings 3 are arranged in two rows corresponding to the rows of the pressure generating chambers 2 of the actuator unit 1.

The storage chamber forming substrate 16 is provided with a plurality of nozzle communication ports 9 communicating with the respective nozzle openings 3.
Spaces corresponding to the first and second ink storage chambers 4A and 4B are formed. The first and second ink storage chambers 4
A and 4B both extend in the direction in which the pressure generating chambers 2 are arranged,
One row of the pressure generating chambers 2 are arranged in parallel at one end of each pressure generating chamber 2. In addition, the first and second
One end of each of the ink storage chambers 4A and 4B is an ink introduction section, and the ink introduction section communicates with the ink introduction port 24. Further, the first and second
The planar shapes of the ink storage chambers 4A, 4B and the like are constituted by smooth curves. By doing so, air bubbles are less likely to adhere to the flow channel, and ejection failure or the like due to the air bubbles is less likely to occur.

In the supply port forming plate 18, first ink supply ports 15A for supplying ink from the first ink storage chamber 4A to the pressure generation chambers 2 are arranged in the direction in which the pressure generation chambers 2 are arranged. The second ink supply port 15B for supplying ink from the second ink storage chamber 4B to the pressure generating chamber 2 is
Are arranged in the direction of arrangement. The first ink supply port 1
The row of 5A and the row of second ink supply ports 15B are arranged side by side on one end side of each pressure generating chamber 2 so that the first and second ink supply ports 15A and 15B are arranged in a staggered manner. Has become. Then, inks of different colors are alternately supplied from the first and second ink storage chambers 4A and 4B to the pressure generating chambers 2 arranged in a line.

The supply port forming plate 18 is provided with a communication port 8 for communicating the pressure generating chamber 2 with the nozzle opening 3, and the first and second ink storage chambers are formed from the nozzle rows 3 arranged in a row. The inks of different colors supplied from 4A and 4B are alternately ejected. Further, the supply port forming plate 18 is provided with four ink introduction ports 24 for introducing ink from an ink cartridge (not shown) into each of the ink storage chambers 4A and 4B in a line in the horizontal direction (scanning direction of the recording head). Is provided. As described above, since the ink introduction ports 24 are arranged in one row in a direction orthogonal to the row of the pressure generating chambers 2, ink can be easily introduced from an ink cartridge or the like, and the structure is not complicated.

In this recording head, one row of pressure generating chambers 2
Two ink storage chambers 4A and 4B communicate with each other,
Two rows of ink are ejected in one row, and printing is performed using four colors of ink on the entire recording head. As shown in FIG. 3, the first and second ink storage chambers 4A, 4A
Nozzle opening 3 for discharging ink of each color in communication with B
(A, B) are alternately arranged with ABAB..., And the nozzle pitch P of the nozzle opening 3 for discharging ink of the same color.
a and Pb are provided so as to have a constant pitch.

As described above, in the recording head, since two different colors of ink are ejected in one row of the pressure generating chambers 2, the size of the recording head itself can be significantly reduced. Can be. Further, even if the number of ink storage chambers is increased by increasing the number of colors of ink to be used, the size of the recording head itself does not need to be so large.

In the above-described recording head, since adjacent nozzle openings 3 eject ink of different colors in the same row of nozzle openings 3, even if the nozzle pitch Pn is narrowed, the same nozzle opening 3 is used. The nozzle pitches Pa and Pb between the colors can be made sufficiently large. Therefore, the nozzle pitch Pn can be made sufficiently small, and the size of the recording head can be reduced, so that a decrease in accuracy at the time of assembling the recording head is reduced, and a decrease in image quality when paper feeding becomes unstable is also reduced. In addition, there is no problem that the space cannot be sufficiently filled or the boundary is visible as in the related art.

FIG. 4 is a view showing an ink jet recording head according to a second embodiment of the present invention, wherein FIG.
FIG. 4B is a cross-sectional view passing through the ink supply port 15A, and FIG. 4B is a cross-sectional view passing through the second ink supply port 15B. In this recording head, the actuator unit 1 and the flow path unit 5
Between the first communication port 15A and the pressure generation chamber 2 and the first pressure generation chamber communication port 31A that communicates with the pressure generation chamber 2, and the second communication port 15B and the second pressure generation chamber communication port that communicates with the pressure generation chamber 2. 31B
The communication port forming plate 30 on which is formed is laminated. In the figure, reference numeral 32 denotes a communication port for communicating the pressure generating chamber 2 with the nozzle opening 3. Otherwise, it is the same as that shown in FIGS. 1 and 2, and the same parts are denoted by the same reference numerals.

In this recording head, the ink that has passed through the first and second ink supply ports 15A and 15B temporarily
In addition, since the ink flows into the pressure generating chamber 2 through the communication ports 31A and 31B of the second pressure generating chamber, the ink flows smoothly. Other than that, the same operation and effect as those shown in FIGS. 1 and 2 are obtained.

FIG. 5 shows an ink jet recording head according to a third embodiment of the present invention. In this recording head,
The first ink supply port 15A and the second ink supply port 15B are not arranged in a zigzag pattern. Instead, one row of the pressure generation chambers 2 is divided into two blocks, and the pressure generation of one block is performed. The chamber 2 is arranged to communicate with the first ink storage chamber 4A, and the pressure generating chamber 2 of the other block is arranged to communicate with the second ink storage chamber 4B. Otherwise, FIGS. 1 and 2
And the same parts are denoted by the same reference numerals.

FIG. 6 shows an ink jet recording head according to a fourth embodiment of the present invention. In this recording head,
The first and second pressure generating chambers 2 are arranged in a row in a row.
Two sets of ink storage chambers 4A and 4B are provided so as to face each other, so that four colors of ink are ejected from one row of pressure generation chambers 2. Otherwise, it is the same as that shown in FIGS. 1 and 2, and the same parts are denoted by the same reference numerals.

In each of the above embodiments, an example is shown in which the present invention is applied to a recording head using a piezoelectric vibrator in a flexural vibration mode. However, the present invention is not limited to this, and a heating element is used as a pressure generating element. The present invention can also be applied to a so-called bubble jet type recording head using the same.

[0041]

As described above, according to the ink jet recording head of the present invention, two different types of ink can be ejected from a single row of pressure generating chambers. The size of the recording head itself can be significantly reduced as compared with a device that discharges color ink.
Further, even if the number of ink storage chambers is increased by increasing the number of colors of ink to be used, the size of the recording head itself does not need to be so large.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an ink jet recording head according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a positional relationship between a pressure generating chamber and an ink storage chamber of the ink jet recording head.

FIG. 3 is an explanatory diagram showing a pitch of a nozzle opening.

FIG. 4 is a cross-sectional view illustrating an ink jet recording head according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a positional relationship between a pressure generating chamber and an ink storage chamber of an ink jet recording head according to a third embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a positional relationship between a pressure generating chamber and an ink storage chamber of an ink jet recording head according to a fourth embodiment of the present invention.

FIG. 7 is an exploded perspective view showing a conventional ink jet recording head.

FIG. 8 is a sectional view of the ink jet recording head.

FIG. 9 is a perspective view showing the ink jet recording head.

FIG. 10 is an explanatory diagram showing an operation of the ink jet recording head.

FIG. 11 is an explanatory diagram showing a printing method of the ink jet recording head.

FIG. 12 is an explanatory diagram showing another printing method of the ink jet recording head.

[Explanation of symbols]

 Reference Signs List 2 pressure generating chamber 3 nozzle opening 6 piezoelectric vibrator 4A first ink storage chamber 4B second ink storage chamber 15A first ink supply port 15B second ink supply port

Claims (6)

[Claims] 1. A plurality of pressure generating chambers are arranged in a row, an ink storage chamber for storing ink supplied to each of the pressure generating chambers is provided, and nozzles communicating with the pressure generating chambers are arranged in a row. An ink jet recording head provided with a pressure generating element for generating pressure in each of the pressure generating chambers and discharging ink droplets from each nozzle, wherein a row of pressure generating chambers is provided for one row of pressure generating chambers. A first ink supply port array having first and second ink storage chambers extending in the first direction and communicating the first ink storage chamber with the pressure generation chamber, and a second ink supply row communicating the second ink storage chamber with the pressure generation chamber. An ink jet recording head characterized in that different types of ink can be ejected in the same nozzle row by arranging an ink supply port row and one end side of each pressure generating chamber. . 2. The ink jet recording head according to claim 1, wherein adjacent nozzles in the same nozzle row discharge different types of ink. 3. The ink jet recording head according to claim 1, wherein different types of ink ejected in the same nozzle row are inks of different colors. 4. The flat shape of the first and second ink storage chambers is constituted by a smooth curve.
4. The ink jet recording head according to any one of items 3. 5. An ink inlet for introducing ink into the first and second ink storage chambers, and the ink inlets are arranged in a row in a direction orthogonal to the row of pressure generating chambers. The inkjet recording head according to any one of claims 1 to 4. 6. The pressure generating chamber according to claim 1, further comprising a first and second pressure generating chamber communication ports for guiding the ink passing through the first and second ink supply ports to the pressure generating chamber. Inkjet recording head.